Reply To: Hardness of steel rod…

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david pierce
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Holy cow, you don’t look like the guy in the videos. As far as the steel goes, if the application is for a pivot, then wear resistance would be an important factor in the material selection. A pivot will rub against an extremely hard bearing surface and must be able to withstand the abrasion. Usually when an entire industry used a particular material for many years it is because it worked. If you watch some of the old videos of the Hamilton Watch Company you can get a strong impression that they put out an immense effort to find the proper materials for watch parts. There may be other materials that have sufficient shock resistance but can be made a little harder and take a better polish than S7. The material that the rest of the watch industry uses is probably the best material for a particular application. We used to use S7 for punch press dogs because in some applications no other material would stand up to the force from the flywheel. Heat treating these items was a bit tricky. If it was too soft it would begin to mushroom, if too hard it would crack. We had to send these out to a heat treating company that had computer controlled vacuum furnaces as the blow tourch and quench when it looked right method could not give us the control needed to make the part work.